This invention relates in general to vaporizers and in particular to a new and useful anesthetic vaporizer having an exchangeable vaporizer chamber.
The invention relates in general to liquid vaporizers and in particular to a new and useful anesthetic vaporizer with a vaporizer chamber into which a gas inlet channel for fresh gas leads and which is connected via an outlet channel with a proportioning unit containing setting means for the anesthetic concentration to be released to the fresh gas.
A similar anesthetic vaporizer has become known through German OS No. 25 07 261.
In anethesis apparatus, anesthetic vaporizers are inserted in the fresh has cycle in order to enrich the fresh gas to be suppliedd to the patient with a desired anesthetic of different, adjustable concentration. For this purpose, the fresh gas line is connected to the anesthetic vaporizer, and a partial stream of fresh gas in branched off into the vaporizer chamber via a line, while the other part is conducted via a by-pass line. The vaporizer chamber stream is saturated with anesthetic vapor and rejoins the fresh gas partial stream from the by-pass line. By setting a control valve in the vaporizer chamber stream, the proportion of the vaporizer chamber steam to the by-pass stream is varied, whereby the desired anesthetic concentration in the fresh gas stream can be adjusted. In the path of the by-pass stream a temperature-dependent control unit extending into the vaporizer chamber is disposed which compensates the temperature influence and permits constant proportioning at different operating temperatures. The anesthetic concentration can be read by means of an indicating unit designed as a scale ring whose position is variable in accordance with the setting of the control valve. After the partial streams have been brought together, the fresh gas enriched with anesthetic is introduced via a gas mixture outlet channel into the respiration system leading to the patient.
In the known anesthetic vaporizer, the vaporizer chamber is firmly connected with the proportioning unit, as one must use a proportioning unit correlated with the particular anesthetic used. Because of the different vapor pressure and different viscosity of the various anesthetics, an identical setting of the control valve leads to different anesthetic concentrations in the fresh gas stream supplied to the patient. Therefore, if during an anesthesia it is necessary to change the anesthetic, the known anesthetic vaporizer plus its proportioning unit must be exchanged in its entirety. Emptying the known vaporizer and subsequently filling it with another anesthetic is not possible, as the inner walls of the vaporizer chamber, and in particular the wicks used for vaporization, are impregnated with the old anesthetic, which would become mixed with the new anesthetic in an uncontrollable manner. For the application of several anesthetics during an anesthesis to be carried out, it is necessary, therefore, to provide a separately calibrated anesthetic vaporizer of the known kind for each anesthetic and to keep it in readiness during performance of the anesthesia. This means considerable cost of manufacture and procurement. Moreover, as a rule, an appropriate receiving space for several anesthetic vaporizers for different anesthetics is provided for this purpose at the apparatus. Therefore, several vaporizers must be connectable to an apparatus using the known vaporizer. If these vaporizers are to be ready and connected during use of the apparatus, a separate supply line for fresh gas and gas mixture for each vaporizer as well as space for accommodating several vaporizers must be provided. These measures increase the weight of an anesthesia apparatus considerably, complicate its handling, and require much space.